Synchrotron high angular resolution microdiffraction analysis of selective area grown optoelectronic waveguide arrays

Abstract

A synchrotron microbeam high-angular resolution diffraction setup based on a phase zone plate and a perfect Si(004) analyzer crystal was introduced to generate an x-ray microbeam with a lateral size of 0.24 µm and an angular resolution of 2 arcsec. The microbeam high angular resolution x-ray diffraction was applied to study InGaAlAs-based multiple quantum well (MQW) ridge-waveguide arrays produced by metal–organic vapour-phase epitaxy in a selective area growth regime with a central waveguide width varying from 1.6 to 60 µm. The analysis of the period T and the strain S in MQW ridge structures determined from the high-resolution diffraction data is presented. It was found that the MQW period is uniform across the ridge within the error bar of ΔT = ± 0.25 nm. Within the waveguide array, the MQW period and strain can be adequately described by a gas-phase diffusion model.